1. Field of the Invention
The present invention relates to an image processing apparatus, and more particularly to an image processing apparatus that corrects deterioration of an image caused by an image pickup optical system at a high resolution and at a high level of quality.
2. Description of the Related Art
With respect to an object taken via an image pickup optical system, light emitted from one point cannot be focused to one point and has a small spread due to the influence of diffraction or aberration generated by the image pickup optical system. The distribution having such a small spread is called a point-spread function (PSF). Due to the influence of the image pickup optical system, a taken image is formed by convolving the PSF into an object image, and as a result the image is blurred and the resolution is deteriorated.
Recently, it has been common that the taken image is stored as electronic data, and a technology of correcting an image deterioration caused by an optical system using an image processing has been proposed. Japanese Patent Laid-Open No. 2010-56992 discloses a method of storing a filter coefficient for correcting the image deterioration to perform an image processing.
However, when the deterioration correction of the image is performed by a filter processing using an image restoration filter, it is necessary that information of an optical transfer function (OTF information) for making the image restoration filter are stored in an apparatus for each pixel. However, since the OTF information is calculated by each of the information of an image pickup element and the image pickup optical system, an amount of the information is significantly large and it is difficult to store all of them in the apparatus.